1,2,4-Triazolo[5,1-a]isoindoles, 1,2,4-triazolo[5,1-a]isoquinolines and the corresponding 5,6-dihydro derivatives, all of them bearing a phenyl group at the 2-position, are known from U.S. Pat. Nos. 4,007,276 and 4,075,341. Imidazo[1,2-a]isoquinolines bearing a phenyl group at the 2-position are known from U.S. Pat. No. 4,075,342. The phenyl groups at the 2-position of the above mentioned heterocyclic structures may be also variously substituted (e.g. by alkoxy, allyloxy, halo, alkyl and so on). The biphenylyl substitution, however, has never been described.